Battery charging device and method for the charging of batteries with several battery blocks

ABSTRACT

Battery charging device and method for charging batteries by means of a power supply module, whereby a battery ( 30 ) comprises a plurality of battery blocks ( 31, 32, 33, . . . , 3   n ) connected in series. The individual battery blocks ( 31, 32, 33, . . . , 3   n ) of the battery ( 30 ) are charged serially one after the other, once per charging cycle for a definable duration, and the charging cycle is repeated so many times until the individual battery blocks ( 31, 32, 33, . . . , 3   n ) have reached a definable state of charge or until the power supply is broken. The invention relates in particular to methods and systems for charging batteries ( 30 ) in electric vehicles, among other things.

This invention relates to a battery charging device and method forcharging batteries by means of a power supply module, whereby a batterycomprises a plurality of battery blocks connected in series. Theinvention relates in particular to methods and systems for chargingbatteries in electric vehicles, among other things.

Rechargeable batteries and corresponding devices for recharging suchbatteries have been known for many years, and are state of the art.Although the batteries and devices for charging batteries availabletoday are still far from satisfying all demands of technology, there area wide range of applications in many technological fields. Among thesefields are not just exotic ones such as space technology and solarenergy technology. In practically all mobile devices as well as in otherapparatus, which have to function for long periods of time e.g. withouthuman surveillance, rechargeable batteries form the backbone for interimstorage of electrical energy. A typical area of application thereby aresolar-powered measuring devices or other apparatus for data acquisition,electromobiles, mobile radio devices, etc. etc. Rechargeable batteries,as the name says, must be periodically charged. For loading, thebatteries are normally connected to the public power supply networkintermittently, via a solar facility by means of solar cells or via agenerator operated with a fuel, such as fossil fuels.

A special area of application of rechargeable batteries are so-calledelectromobiles, i.e. automobiles with electric drive. The enormoussuccess of the automobile in the twentieth century has led to anunbelievable flood of automobiles on the road. This has had theinevitable consequence that the negative aspects of automobiles withcombustion engines based on fossil raw materials have developed intodifficult-to-solve problems. Among these problems are, in particular,the pollutant exhaust of CO, CO₂, etc., but also the declining supply ofthe natural resources of such raw materials. It may be said that theexhaust of “greenhouse gases”, such as the mentioned CO₂, is viewed byscientists today as one of the greatest threats to the further existenceof humankind on the earth. Climatic catastrophes and lack of equilibriumin the water balance of the seas are only two of the possible horrorscenarios. Nevertheless hardly anyone seems willing to give up themobility achieved in the last century. It must therefore be among theprimary goals of scientific research to find ways out of the dilemma andthe catastrophe looming ahead. Electromobiles and other vehicles basedon electric drive could play an important role in the near future insolving the mentioned problems.

In order to be able to power the electromotors of the electromobiles,they are normally equipped with batteries for interim storage of theelectrical energy needed. The performance or efficiency of suchelectromobiles are greatly determined by the features of the battery andtheir optimal battery management. Important parameters thereby are,inter alia, costs and weight of the batteries, number of possible cyclesof recharging, charging speed, simplicity of handling, disposability,etc. Experiments with different batteries show that lead accumulatorstorage batteries (lead-acid) generally have a lower energy density anda shorter life cycle than e.g. cadmium-nickel storage batteries ornickel-metal hybrid accumulators, such as iron-nickel storage batteries.Unfortunately the batteries with a high energy density and more lifecycles are also significantly more expensive. For appliances with lowpower consumption, such as mobile radio devices, etc., the cost factorfor the battery does not carry that much weight. In the case of deviceswith high electricity requirements, such as electromobiles, the costfactor for the batteries takes on a completely different dimension. Theprice of the batteries can therefore play a decisive role in theseareas. One of the questions related thereto is whether the life cyclesof the batteries can be improved by means of better battery management,in particular charging technology.

Used, among other things, for devices with high power needs arebatteries with individual battery cells connected in series. For suchseries connections of accumulator batteries, charging devices exist inthe state of the art which charge the entire battery string consistingof the various battery blocks via an overall voltage. The voltage of thecharging device thereby corresponds to the charging voltage of thebattery string. With such charging methods, however, it is difficult tocontrol the individual cell voltages and charging currents. This has thedrawback, inter alia, that, when the charging is prematurely terminated,the battery cells have different states of charge. In the use ofelectromobiles, however, it is frequently even desirable for a user tobe able to interrupt the charging of the batteries at any particularmoment in the charging process. A further drawback is that in suchcharging systems the voltages of the individual cells can reach suchhigh values that an increased production of hydrogen and oxygen occurs.Above all with maintenance-free batteries, this leads to a loss ofwater. The consequence is corrosion of the upper part of the lead grid(cf. FIG. 5). This effect leads to premature failure, i.e. a shortenedlife of the cell. In addition, with the charging methods of the state ofthe art it is difficult to determine optimally the so-calledend-of-charge condition without ending up thereby with an overchargingof individual battery blocks. Such an over-charge can lead to seriousdamage in certain types of rechargeable batteries and likewise shortentheir life significantly. In the scientific literature (see e.g. PavlovD., Petkova G., Dimitrov M., Shiomi M. and Tsubota M., “Influence offast charge on the life cycle of positive lead-acid battery plates,Journal of Power Sources 87 2000, pp. 39-56), it has been known foryears that, with certain batteries, the life is improved in cycleoperation through use of high charging currents. This could be confirmedwith our experiments on the test rig of the HTA Biel-Bienne (Hochschulefür Technik und Architektur Biel-Bienne) (University for Technology andArchitecture Biel-Bienne) (concerning this see Meier-Engel, Karl,VEBILA, “Verbesserung der Lebensdauer von Batterien mit einemintelligenten Ladegerät;” (Improvement of the life of batteries with anintelligent charging device), Annual Report 2000 HTA Biel-Bienne,Department of Automobile Mechanics). The advantage of using highcharging voltages for charging often cannot be availed of because, amongother things, the costs of the charging devices climb sharply withincreasing power.

It is the object of this invention to propose a new method and system ofcharging batteries with a plurality of battery blocks which does nothave the described drawbacks. In particular, it should be possible todetermine precisely the end-of-charge conditions, to use higher chargingvoltages, to shorten the charging cycles, and to interrupt the chargingprocess at any time without the individual battery cells of theaccumulator having greatly differing states of charge. At the same time,the costs for such a battery charging device should be kept withinaffordable limits by means of the invention.

This object is achieved according to the invention through the elementsof the independent claims. Further advantageous embodiments followmoreover from the dependent claims and from the description.

In particular these objects are achieved by the invention in thatbatteries with a plurality of battery blocks or respectively batterycells are charged by means of a power supply module, the individualbattery blocks of a battery being charged serially one after the other,once per charging cycle, for a definable duration, and the chargingcycle is repeated so many times until the individual battery blocks havereached a defined state of charge or until the power supply via thepower supply module is disconnected. This embodiment variant has theadvantage, among other things, that higher charging currents can be usedfor charging the batteries than in the state of the art. In addition,the end-of-charge conditions can be more precisely determined. Anotheradvantage is that the charging cycle is shortened even with lowercharging currents. If the charging of the battery is prematurelyinterrupted, it can be ensured through the multiple serial charging thatthe individual battery blocks do not exceed a maximal, predefinablecharge difference, i.e. the battery blocks are in close to the samestate of charge even with a premature termination of the charging, whichresults in further advantages. Further advantages are, among otherthings, that the power supply module only has to be designed for onebattery block. Thus the costs of producing the power supply module canbe reduced. Since each battery block is individually charged, thevoltage and the temperature of the individual battery block can, asmentioned, be monitored and maintained exactly. During the pauses in acharging cycle, the battery blocks can cool off. As a further advantage,the above-mentioned features and advantages result in a higher chargingcycle number and a longer life of the batteries.

In an embodiment variant, the switching from one battery block to thenext takes place automatically during a charging cycle by means of achangeover switch. The changeover can take place e.g. electronicallyand/or in an electronically controlled way. This embodiment variant hasthe advantage, among other things, that the charging can take placewithout the help of a user.

In a further embodiment variant, the charging of an individual batteryblock per charging cycle takes place for a duration of 30-300 seconds.This has the advantage, among other things, that with a prematuretermination of the charging the battery blocks do not have chargedifferences which are too great. Furthermore, in this time span, theratio of charging amperage to heating up of the battery can beoptimized. Thus a battery block can e.g. cool off sufficiently duringcharging of the other battery blocks, so that no damage arises in thebattery blocks owing to overheating. This overheating of the batteries,or respectively battery blocks, during charging with conventionalmethods is one of the main problems of the state of the art.

In another embodiment variant, each charging of an individual batteryblock per charging cycle corresponds to a capacitance of 1/240 to 1/12of the overall capacitance. This embodiment variant has the sameadvantages, among other things, as the preceding embodiment variant.

In an embodiment variant, per battery block, the charging current isswitched on and off by means of two electronic switches. The electronicswitches can comprise e.g. one or more MOS-FET transistors. Thisembodiment variant has the advantage, inter alia, that with the MOS-FETtransistors a cost-efficient design of the electronic switch is involvedin which standard state-of-the-art components available on the marketcan be used.

In a further embodiment variant, a control device with a microprocessorcontrols the electronic switches and/or functions of the power supplymodule for charging batteries. As a variant, the control device can,with a microprocessor, measure at least voltage and/or temperature ofthe battery block which is being charged, and control the charging cyclebased on the measured data. Furthermore the control device with themicroprocessor can be programmed such that the charging cycle is endedupon reaching a pre-definable charging characteristic. This embodimentvariant has the advantage, among other things, that the charging of thebatteries can be controlled in a way which is automatic and controllablefor the user.

It should be stated here that, besides the method according to theinvention, the present invention also relates to a system for carryingout this method. Furthermore it is not limited to rechargeable batteriesof electromobiles, but (it relates) in a completely general way tobatteries with a plurality of battery blocks connected in series.

Embodiment variants of the present invention will be described in thefollowing with reference to examples. The examples of the embodimentsare illustrated by the following attached figures:

FIG. 1 shows a block diagram showing schematically the architecture ofan embodiment variant of a battery charging device according to theinvention for charging batteries 30 with a plurality of battery blocks31, 32, 33, . . . , 3 n.

FIG. 2 likewise shows a block diagram showing schematically thearchitecture of an embodiment variant of a battery charging deviceaccording to the invention for charging batteries 30 with a plurality ofbattery blocks 31, 32, 33,. . . , 3 n in more detail than in FIG. 1.

FIG. 3 shows a measurement diagram showing schematically the voltagecourse of the individual battery blocks during the charging. In theI-phase a constant current is used for charging. During this chargingphase, the battery blocks can have different voltages, as in thisdiagram.

FIG. 4 shows a measurement diagram showing schematically the voltagecourse of the individual battery blocks during the charging. In theU-phase, the voltage is set to a fixed value. During this chargingphase, the battery blocks can have different currents as in thisdiagram.

FIG. 5 shows the positive electrode of a test battery after a life cycletest. The positive electrode shows strong corrosion of the grid in theupper portion, which was evidently increased by water loss.

FIG. 1 illustrates an architecture which can be used to achieve theinvention. In this embodiment example, the battery charging device forcharging batteries comprises a power supply module 10, whereby a battery30 comprises in each case a plurality of battery blocks 31, 32, 33, . .. , 3 n connected in series. The batteries 30 can be e.g. leadaccumulator storage batteries (lead-add), cadmium-nickel storagebatteries, nickel-metal hybrid accumulators, such as iron-nickel storagebatteries, batteries of fuel cells, such as e.g. solid oxide fuel cell(SOFC), proton exchange membrane fuel cell (PEM-FC) or direct methanolfuel cell (DMFC), super capacitors (supercaps) and/or ultra-capacitors(ultracaps). For mobile applications, such as, for example, motorvehicles or respectively electromobiles, which use batteries based onfuel cells, fuel cell types with comparatively low operating temperaturesuch as PEM-FC are especially suitable. The battery charging deviceaccording to the invention very generally relates, however, torechargeable batteries consisting of a plurality of battery cells orrespectively battery blocks connected to one another. The individualbattery blocks 31, 32, 33, . . . , 3 n of a battery 30 are chargedserially one after the other, once per charging cycle, for a definableduration by means of switches 40/41, and the charging cycles arerepeated so many times until the individual battery blocks 31, 32, 33, .. . , 3 n have reached a definable state of charge or until the powersupply via the power supply module 10 is disconnected. Meant by adefinable state of charge is not that the charging cannot be prematurelyinterrupted. On the contrary, it should thereby be assumed that thestate of charge of the battery 30 is simply determined differently inthe case of a premature interruption of the charging. In the batterycharging device the changeover can take place automatically and/orelectronically and/or in an electronically controlled way. The switchingon and off of the charging current per battery block or respectivelybattery cell can be achieved by means of two electronic switches 40/41.The electronic switches 40/41 can comprise e.g. at least one MOS-FETtransistor. Such an embodiment variant thereby has the advantage thatMOS-FET transistors are relatively cost-effective standard componentswhich are therefore also easily obtainable. Charging current can besupplied to a battery block 31, 32, 33, . . . , 3 n per charging cyclee.g. for a duration of 30-300 seconds and/or with a capacitance of 1/240to 1/12 of the overall capacitance per charging cycle. In an embodimentexample described here, the battery 30 comprises e.g. battery cells 31,32, 33, . . . , 3 n each with 12 V. The charging current amounted, forexample, to 0.5 C or more, and the charging time was, as described,30-300 seconds. The charging current can be supplied via the powersupply module 10, which is connected e.g. to the public power supplynetwork and/or solar cells and/or a fossil-fuel-based power generator,etc. Depending upon current supply, the power supply module 10 cancomprise an AC/DC converter. The charging process is continued e.g.until the connection to the public power supply network is disconnectedor the batteries are completely charged. The electronic and/orelectronically controlled changeover can take place by means of acontrol device 20, whereby the control device 20 can comprise one ormore microprocessors and/or storage modules. The control device 20controls and monitors the electronic switches 40/41 and/or the functionsof the power supply module 10. Thus, for example, the charging cycle canbe interrupted by means of the control device 20 when a definablecharging characteristic has been achieved. In an embodiment variant, thecontrol device monitors in particular the charging parameters, e.g.periodically, such as, for example, voltage and temperature of theindividual battery blocks and/or batteries. The voltage regulation cantake place preferably in dependence upon the battery temperature. Forelectrical connections between power supply module 10, control device 20and switches 40/41, e.g. ribbon cable and/or single cable can be used.For transmission of measurement signals, a data bus can connect thecontrol device 20 to the corresponding measurement devices.

FIG. 2 illustrates an architecture which can be used to achieve theinvention. This embodiment example comprises the same features as theembodiment example according to FIG. 1. The description of FIG. 1,including the reference numerals, applies in an identical way also toFIG. 2, FIG. 2 showing a more detailed representation of an embodimentexample. In particular, the electrical connections between the powersupply module 10, the control device 20 and switches 40/41 arespecifically shown, without however the general nature of the batterycharging device or of the method for charging batteries being therebylimited in any way. As described, the electrical connections can beachieved e.g. with ribbon cable and/or single cable. For transmission ofmeasurement signals and/or the control signals, a data bus can connectthe control device 20 to the respective measuring devices orrespectively switches 40/41. In FIG. 2, the reference numeral 21indicates the measurement lines, i.e. the connection of the control unit20 to the measuring devices, whereby the signals for measuring thevoltage and/or the temperature and/or further state of charge parameterscan be transmitted to the control unit 20. The state of chargeparameters are measured directly at the individual battery blocks 31,32, 33, . . . , 3 n of the battery 30 to be charged. Reference numeral22 represents the control lines, i.e. the connections for transmissionof the control commands for switching of the switches 40/41. In FIG. 2the switches 40/41 are now shown separately, the reference numerals 40being, for instance, electronic switches, such as e.g. MOS-FETtransistors, for interruption of the positive connection, whereas thereference numerals 41 are, for example, electronic switches, such ase.g. MOS-FET transistors, for interruption of the negative connection.The power supply module 10, as shown in FIGS. 1 and 2, can be producedwith commonly available components, e.g. of the company VICOR (cf. VICORProduct User Guide (2000), http://www.vicr.com). One possiblerealization would be achieved e.g. with a VI-ARM-C12 input module (in:90 to 264 VAC at 750 W max. temperature range: −25° C. to 85° C.)together with a VI-261-CU-BM DC-DC converter (in: 300 VDC, out: 12 VDCat 200 W, temperature range: −25° C. to 85° C.) and a VI-B61-CU-BMbooster module (in: 300 VDC, out: 12 VDC at 150 W, temperature range:−25° C. to 85° C.). It is to be pointed out, however, that such powersupply modules 10 belong to the state of the art, just as themanufacture of the power supply module 10 is known to one skilled in theart in this field both in this design as well as in any other design.These mentioned VICOR components could be configured, for example, in acooling body and with a housing secured against contact with persons.With suitable construction, the power supply module 10 should also getby without cooling, e.g. through a cooling ventilator. The outputvoltage of the power supply module 10 can e.g. be monitored by theelectronic control device 20 and can be regulated via the input voltageV_(in). The charging current can be controlled via the input currentI_(in). In this embodiment example, the control device 20 comprises fourmodules: a module for measuring the temperature and the voltage of theindividual battery blocks, optionally with a 230 V detection (describedfurther below), a microprocessor, an output module and a driver module.The modules can be accommodated e.g. in a metal housing, the connectiontaking place with ribbon cable. In another embodiment example, theconnection can also take place e.g. via a bus system. The temperaturemeasurements at the battery blocks 31, 32, 33, . . . , 3 n can be taken,for instance, by means of temperature sensors. A possibility thereforfrom the state of the art would be the use of a temperature sensorKTY-10 of the Siemens company. In this embodiment example, this would befed directly with the voltage source of the microprocessor, which hasthe advantage that the measurement value can be supplied directly to themicroprocessor. By means of a potentiometer, the temperature can becorrespondingly calibrated. In the same way it is possible to measurethe temperature at further battery blocks 31, 32, 33, . . . , 3 n. Thevoltage measurement of the individual battery blocks 31, 32, 33, . . . ,3 n can be carried out with printed circuit board relays. These areswitched on by the microprocessor as soon as the respective batteryblock 31, 32, 33, . . . , 3 n is charged. The supply of the printedcircuit board relays can take place e.g. with 12 V. If the battery 30 isused in an electromobile, the board voltage of the electromobile can beused. The activation of one or more microprocessors can take place viaoptical couplers and/or transistors, an electric locking preventing twoprinted circuit board relays from being switched at the same time. Inthe embodiment example, the measurement values are supplied to the atleast one microprocessor via a buffer amplifier. Before the bufferamplifier the voltage of the battery block is reduced to a factor of0.294 of the voltage. Thus at the microprocessor a voltage of 5 Vcorresponds to a voltage of 17 V at the battery blocks 31, 32, 33, . . ., 3 n. The voltage can be calibrated e.g. by means of potentiometer. Inthis embodiment example, a DC/DC converter supplies the buffer amplifierinput with voltage. The output of the buffer amplifier is supplied withvoltage from the DC/DC converter of the microprocessor. The mentioned230 V detection can be used to determine whether the battery chargingdevice, which is located e.g. in an electromobile, is connected to apower supply such as the public power supply network or not. With anoptical coupler HP HCPL3700, the alternating current can be rectified,and digital signals can be generated for the microprocessor.

The microprocessor is usually installed on a mother board or a printedcircuit board. Supply can take place via a DC/DC converter and a 5 Vregulator. For programming the computer, one of the common programminglanguages can be used. During electronic control of the changeover fromone battery block to the next, the switching is controlled by themicroprocessor. The charging time of a battery block in this embodimentexample is preferably 30-300 seconds. However, other times are alsoconceivable in principle. Optimized preferably during this processshould be the relationship of the magnitude of the charging current andthe heating of the battery block together with the cooling off phasesduring the charging of the other battery blocks. The described voltageV_(in) of the power supply module 10 can be generated via an analogoutput. The charging terminal voltage can be calibrated e.g. via apotentiometer. The control of the output current has been achieved inthis embodiment example by means of two digital outputs. Two differentcurrents can thereby be controlled, for example during the I-phase. Inthe present embodiment example, a distinction has been made betweenI-phase and U-phase for the charging process. During the I-phase, eachbattery block is charged with a constant current, e.g. 30 A, amountingto at least 0.5 C, however. During this phase, the battery blocks canhave different voltages, as shown in FIG. 3 for the charging of abattery with 3 battery blocks. The time axis t in FIG. 3 indicates thetime in minute units. During the U-phase, on the other hand, charging iswith a constant voltage. Now the battery blocks can thereby havedifferent currents. The U-phase is shown in FIG. 4, likewise for abattery with three battery blocks. Again the time axis t in FIG. 4indicates the time in minute units. In the diagram shown, for example,the charging current of the third battery block is clearly higher thanthat of the battery blocks 1 and 2.

By means of this architecture, the embodiment example described here hasthe advantage that higher charging currents can be used for charging thebattery than in the state of the art. The end-of-charge conditions canalso be thereby determined more precisely. Another advantage is that thecharging cycle is shortened, even with lower charging currents. Shouldthe charging of the battery be prematurely interrupted, it can beensured through the multiple serial charging that the individual batteryblocks do not exceed a maximal, predefinable charge difference, i.e. thebattery blocks are in close to the same state of charge even with apremature termination of the charging. The embodiment example also hasthe advantage that the power supply module only has to be designed forone battery block. The costs of producing the power supply module canthus be reduced. Since each battery block is individually charged, thevoltage and the temperature of the individual battery block can bemonitored and maintained exactly. During the pauses in a charging cycle,the battery blocks can cool off. As a further advantage, theabove-mentioned features and advantages result in a larger number ofcharging cycles and a longer life for the batteries. The drawbacks ofthe state of the art, such as overheating of the batteries and lowercharging currents, can thus be avoided. FIG. 5 shows the picture of apositive electrode, damaged through the charging cycles, of a testbattery (HAWKER GENESIS 37 Ah) after charging with a conventionalcharging method, the charging current having been applied over theentire battery. The positive electrode of the test battery displaysstrong corrosion in the upper portion of the grid. The microfiberglassseparator of this maintenance-free battery is relatively dry, from whichit can be concluded that the above-mentioned drawbacks of the state ofthe art have led to too high a water loss, which accelerated thecorrosion of the battery.

In the present embodiment example, the output signals of themicroprocessor are relayed to the driver module with a potentialseparation. For electromobiles, for example, the control of the vehicledrive can be switched off as soon as the battery charging deviceoperates by closing a relay provided therefor. In this way it can beensured that the driver does not drive away with the vehicle while theelectromobile is still connected to the public power supply network bymeans of the charging plug. For indication of the end of the chargingprocess, e.g. an NPN small signal transistor can be used, for example.This becomes conductive as soon as the charging is terminated, and thusgenerates an external signal. Depending upon embodiment example, it canmake sense for different operational conditions of the battery chargingdevice to be displayed. Examples of such battery states are: batterycharging device is in operation, alarm temperature (battery orrespectively battery block is too hot), charging cycle or chargingprocess is completed. The maximal value of the charging current can beadjusted e.g. by means of a relay via I_(in). In addition, a secondcharging current can also be controlled by means of a potentiometer, ifsuch a second charging current is necessary in an embodiment. Thus, ifneed be, a second I-phase can be generated. The printed circuit boardrelays for switching on the battery block can be integrated e.g. intothe driver module. One relay each can thereby be used for each batteryblock for control of the changeover 40 at the positive pole and onerelay for control of the changeover 41 at the negative pole. The controlvoltage necessary therefor for the positive and the negative pole can begenerated e.g. through a DC/DC converter.

Used for the electronic switches 40/41 in this embodiment example areFET-MOS-FET <sic. MOS-FET> transistors. This has the advantage, amongother things, that with the MOS-FET transistors a cost-efficient designof the electronic switches is involved in which standardstate-of-the-art components available on the market are used. Otherdesigns for the switches 40/41 are conceivable, however. Thus, forexample, instead of the MOS-FET transistors, any other semiconductor ora relay can be used in order to achieve the switching of the chargingcurrent. Since MOS-FET transistors have an inverse diode, their effectmust be broken with a diode since otherwise the potential separation ofthe individual battery blocks could not be ensured. Temp-FET transistorswere used for the embodiment example which are automatically switchedoff in the case of excess temperature. Thus an overheating of thetransistor cannot cause any failure of the transistor. Transmission ofthe control signals can take place e.g. via cable or a data bus.

It is important to point out that the number of battery blocks, orrespectively battery cells, per battery is not limited by the deviceaccording to the invention for charging such batteries. Thus it isconceivable that in the case of a large number of battery blocks aplurality of charging devices are used in parallel. The method accordingto the invention and the device according to the invention is therebyexpandable, scalable and individually adaptable to the given needs, asdesired. This advantage as such cannot be found in the state of the art.It should likewise be stated here that, despite the detailed descriptionof the embodiment example, the subject matter of the invention disclosedby the description and the claims is not to be viewed as limited in anyway by the technical details indicated. On the contrary, the subjectmatter according to the invention relates in a completely general way tobattery charging devices and methods for charging batteries comprisingone or more battery blocks or battery cells connected to one another.

1. A method for charging batteries by means of a power supply module(10), whereby a battery (30) comprises a plurality of battery blocks(31, 32, 33, . . . , 3 n) connected in series, wherein the individualbattery blocks (31, 32, 33, . . . , 3 n) of a battery (30) are chargedserially one after the other, once per charging cycle, during adefinable duration, and the charging cycle is repeated so many timesuntil the individual battery blocks (31, 32, 33, . . . , 3 n) havereached a definable state of charge or until the power supply via thepower supply module (10) is disconnected.
 2. The method for chargingbatteries according to claim 1, wherein during a charging cycle theswitching over of the charging from one battery block (31, 32, 33, . . ., 3 n) to the next takes place automatically.
 3. The method for chargingbatteries according to claim 2, wherein during a charging cycle theswitching over of the charging from one battery block (31, 32, 33, . . ., 3 n) to the next takes place electronically.
 4. The method forcharging batteries according to one of the claims 1 to 3, wherein thecharging of an individual battery block (31, 32, 33, . . . , 3 n) percharging cycle takes place for a period of 30-300 seconds.
 5. The methodfor charging batteries according to one of the claims 1 to 4, whereineach charging of an individual battery block (31, 32, 33, . . . , 3 n)per charging cycle corresponds to a capacitance of 1/240 to 1/12 of theoverall capacitance.
 6. The method for charging batteries according toone of the claims 1 to 5, wherein, per battery block (31, 32, 33, . . ., 3 n), the charging current is switched on and off by means of twoelectronic switches (40/41).
 7. The method for charging batteriesaccording to claim 6, wherein the electronic switches (40/41) compriseat least one MOS-FET transistor.
 8. The method for charging batteriesaccording to one of the claims 6 or 7, wherein a control device (20)with a microprocessor controls the electronic switches (40/41) and/orfunctions of the power supply module (10).
 9. The method for chargingbatteries according to one of the claims 1 to 8, wherein a controldevice (20) with a microprocessor measures at least voltage and/ortemperature of the battery block (31, 32, 33, . . . , 3 n) which isbeing charged, and controls the charging cycle based on the measureddata.
 10. The method for charging batteries according to one of theclaims 1 to 9, wherein the control device (20) with the microprocessoris programmed such that the charging cycle is ended upon attaining apre-definable charging characteristic.
 11. A battery charging device forcharging batteries which comprise a plurality of battery blocks (31, 32,33, . . . , 3 n) connected in series, the battery charging devicecomprising a power supply module (10), wherein the battery chargingdevice comprises a changeover switch, by means of which the individualbattery blocks (31, 32, 33, . . . , 3 n) of a battery (30) arechargeable and/or rechargeable serially one after the other, once percharging cycle, during a pre-determinable period of time, and thebattery charging device comprises a control device (20) by means ofwhich so many charging cycles are programmable until the individualbattery blocks (31, 32, 33, . . . , 3 n) have reached a definable stateof charge.
 12. The battery charging device according to claim 11,wherein the battery charging device comprises an automatic changeoverswitch by means of which the individual battery blocks (31, 32, 33, . .. , 3 n) of the battery (30) are chargeable and/or rechargeable seriallyone after the other, once per charging cycle, during a pre-determinableperiod of time.
 13. The battery charging device according to claim 11,wherein the battery charging device comprises an electronic changeoverswitch by means of which the individual battery blocks (31, 32, 33, . .. , 3 n) of the battery (30) are chargeable and/or rechargeable seriallyone after the other, once per charging cycle, during a pre-determinableperiod of time.
 14. The battery charging device according to one of theclaims 11 to 13, wherein the charging of an individual battery block(31, 32, 33, . . . , 3 n) per charging cycle comprises a chargingduration of 30-300 seconds.
 15. The battery charging device according toone of the claims 11 to 14, wherein each charging of an individualbattery block (31, 32, 33, . . . , 3 n) per charging cycle correspondsto a capacitance of 1/240 to 1/12 of the overall capacitance.
 16. Thebattery charging device according to one of the claims 11 to 15, whereinper battery block, the charging current is switchable on and off bymeans of two electronic switches (40/41).
 17. The battery chargingdevice according to claim 16, wherein the electronic switches (40/41)comprise at least one MOS-FET transistor.
 18. The battery chargingdevice according to one of the claims 16 or 17, wherein the controldevice (20) of the battery charging device comprises a microprocessorwhich controls the electronic switches (40/41) and/or functions of thepower supply module (10).
 19. The battery charging device according toone of the claims 11 to 18, wherein the control device (20) of thebattery charging device comprises a microprocessor which measures atleast voltage and/or temperature of the battery block (31, 32, 33, . . ., 3 n) which is being charged, and controls the charging cycle based onthe measured data.
 20. The battery charging device according to one ofthe claims 11 to 19, wherein the control device (20) with themicroprocessor is programmable such that the charging cycle is endedupon attaining a pre-definable charging characteristic.